package chapter10.Demo01;
import java.sql.*;
import java.util.Scanner;

public class Demo01 {
    public static void main(String[] args) throws SQLException{
        // 修改用户名和密码
        /**
         * 1. 注册驱动
         * 2. 获取连接
         * 3. 创建表结构对象
         * 4. 执行SQL语句
         * 5. 操作返回结果
         * 6. 关闭连接
         */
        Statement stmt = null;
        ResultSet rs = null;
        Connection conn = null;
        try {
            //1. 注册数据库的驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2. 通过DriverManager获取数据库链接
            String url = "jdbc:mysql://localhost:3306/jdbc?serverTimezone = GMT%2B8&useSSL=false";
            String username = "root";
            String password = "123456";
            conn = DriverManager.getConnection(url, username, password);
            /**
             *  静态sql语句用Statement
             *  动态sql语句用PreparedStatement
             */
            Scanner sc = new Scanner(System.in);
            System.out.println("请输入你的旧帐号名：");
            String n1 = sc.next();
            System.out.println("请输入你的旧密码：");
            String p1 = sc.next();
            System.out.println("请输入你的新账号名：");
            String n2 = sc.next();
            System.out.println("请输入你的新密码：");
            String p2 = sc.next();

            String updateSQL = "update users set name = ?,password = ? where name=? and password=?";
            PreparedStatement ps = conn.prepareStatement(updateSQL);
            ps.setString(1,n2);
            ps.setString(2,p2);
            ps.setString(3,n1);
            ps.setString(4,p1);
            int res =  ps.executeUpdate();
            System.out.println(res);
            if (res>0){
                System.out.println("账号密码更新成功");
            }else{
                System.out.println("账号密码更新失败");
            }
        } catch (ClassNotFoundException e) {
            e.getStackTrace();
        } finally {
            // 6.回收数据库资源
            if (rs != null) {
                try {
                    rs.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                rs = null;
            }
            if (stmt != null) {
                try {
                    stmt.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                    stmt = null;
                }
            }
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                conn = null;
            }
        }
    }
}